It is common practice to provide either a split or a multiple piece casing within which to house the transmission mechanism. This approach has heretofore been employed in order to provide access to the interior of the casing. Such access is deemed necessary to insert and assemble not only the components of the transmission but also the bearings to support the rotatable members of the transmission mechanism. When one employs either split or multiple piece casings, gaskets and a plurality of fasteners are required to secure the casing in its assembled condition.
When one or more gaskets are employed to seal the casing, several factors must be taken into consideration. Most importantly, the casing must have sufficient rigidity to assure that the surfaces that engage the sealing gaskets will maintain their structural integrity in order to maintain the requisite seal. This generally requires the use of additional material to make the casing, and even then, special considerations may need to be given to the particular structural configuration necessary to impart the desired rigidity to the casing.
Each accommodation required to assure that either a split or a multiple piece casing will provide the desired results increases the costs of providing such a transmission. As such, the benefits to be achieved by the adoption and use of a one-piece casing are apparent but have remained elusive inasmuch as the designs heretofore available do not obviate all the deficiencies experienced with the historic split or multiple piece casings.